Valve-gear



(No Model.)

H. F. SHAW.

VALVE GEAR.

No. 388,080. Patented Aug. 21, 1888.

Iliy. 1.

N. PETERS. map-mm", Winhlngon, D. c.

NITED STATES PATENT Erica.

HENRY F. SHAW, OF BOSTON, MASSACHUSETTS.

VALVE-GEAR.

SPECIFICATION forming part of Letters Patent No. 388,080, dated August 21, 1888.

Application filed July 11, 1887. Serial No. 244,045. (No model.)

To aZZ whom, it may concern.-

Be it known that I, HENRY F. SHAW, a citizen of the United States, residing at Boston, in the county of Suffolk and State of Massachusetts, have invented a new and useful Improvement in Valve-Gears,of which the following is a specification, reference being had to the accompanying drawings.

My invention relates to valve-gear for operating a slide-valve, and is especially useful in locomotives.

The object of my invention is to open and close each inlet-port rapidly, and to open the exhaust-port quickly, and allow it to remain open for a long time for each stroke ofthe piston. This I accomplish by having the motion of the valve in either direction the union of two movements, one effected by swinging a link bodily and the other by rocking thelink, the swinging and rocking motions of the link being caused by means of eccentrics on the axle of the driving-wheels of the locomotive, or on the main shaft of an engine, as hereinafter set forth.

In the drawings, Figure 1 is a side view, and Fig. 2 a plan,of so much of one side of a locomotive provided with valve-gear embodying my invention as is necessary for illustration of the same. Fig. 3 is a side view, and Fig. 4 a front view and section of details.

The frame A, driving-wheel B, axle G, connecting-rod D, crosshead E, cylinder F, and valve-chest G,containing the slide-valve, may be those of an ordinary locomotive. To the frame or stand thereon I pivot a lever, H, ata. To the upper end of the leverHis pivoted the reversing-link I,the pivot-pin I) being in a long hearing at the upper end of the lever. This pin is fixed at one end to the link, and at the other end to an arm or lever, J.

On the axle G, fasten two eccentrics, K and L, set quartering or approximately so with reference to each other, and the one K having its center in the same radial direction from the center of the axle as the crank-pin 0. A connecting-rod, M, is fixed at one end to the strap on the eccentric K, and is pivoted at the other end to the lower end of the lever H. A like rod, N, is fixed at one end to the strap on the eccentric L, and is pivoted at the other end to the lower end of the arm or lever J.

On the link I may slide a block, (Z. To this engine in one direction.

block is pivoted a rod, 0, which is pivoted at the other end to a block, 0, which may slide on a guide,f, and to which the outer end of the valve-stem g is fixed. The valve may be an ordinary D-valve.

Ashaft, P, in a bearing, h, has fixed thereto two arms, 2' and j. To the arm 2' is pivoted a connecting-piece, k, which is also pivoted to the rod 0. To the arm j is pivoted one end of a rod, 1, which is pivoted at the other end to the ordinary shippinglever Q. The shaft P may extend across the locomotive and serve a purpose at the other side similar to that illustrated by the mechanism shown,thevalvegear on the other side being like that shown, the eccentrics being suitably located on the axle O to get the required movement of the valve on that side.

In operation the eccentric K will cause, by means of the rod M and lever H, the link I to swing bodily, and,owing to the position of this eccentric with reference to the crank-pin c, this movement will occur mainly when the piston is at and near the middle of its stroke. The eccentric L will, by means of therod N and arm or lever J, cause a rocking motion of the link I, and on account of the position of this eccentric on the axle 0 this movement will be fastest when the piston is at and near the end of its stroke. The movement of the valve, caused by swinging the link bodily, is such as is required to move it over the lap, and is substantially the same whatever the position of the block d on the link. Rocking thelink causes the valve to move over an inlet-port, the distance of this movement being according to the distance of the block (1 above or below thepivotal center of the link. The direction ofmovement of the valve to give a forward or back ward travel of the locomotive will be according to whether the block d is above or below the pivotal center of the link. Thus it appears that either inlet-port will be opened and closed quickly, and the appropriate exhaustport opened quickly,and will be kept open for a long time for each stroke of the piston.

My invention is also useful forstationary engines, in so far as adapted for movement ofthe Such application, as

well as certain modifications-such, for instance, as the substitution of a lever of either of the other forms for the lever Hto carry out my invention and adapt it as required,willbe readily understood.

I claim as my invention-e 1. The combination of two eccentrics, K and L, fixed on the same axle or shaft,the center of one, K,of the eccentrics being in substantially the same radial direction from the center of the axle or shaft as the crank-pin, and the eccentrios being set quartering,or approximately so,with reference to each other, a lever, H,pivoted on the frame of the engine and connected with the eccentric K by means of a rod, M, a link, I, pivoted to said leyer H, and means, substantially as thelever J, fixed to said link, whereby the link is connected with the other eccentric by means of a rod, N, substantially as and for the purposes set forth.

2. In combination with a orank-pin, c, and

two eccentrics, K and L, fixed on an axle or shaft, as specified, two rods, M and N, a lever, H, pivoted on the frame of the engine, a reversing-link, I, pivoted to the lever H, an arm or lever, J, fixed to said link, a block,d, to slide on said link, a rod, 0, and valve-stem 9, substantially as and for the purposes set forth.

3. In combination with an eccentric,K, fixed on an engine shaft or axle,O, a rod, M, alever, H, pivoted on the frame of the engine, and a reversing-link, I, pivoted to the lever H and connected with the slide-valve for operating the same and admitting steam to the cylinder, substantially as specified.

HENRY F. SHAW.

Witnesses:

EDW. DUMMER, ANDREW T. MoCoY. 

